@OmSigDAVID,
It's gamma minus phonetic spelling for bishop. You're style is beta minus Dave. An affectation of those members of the chattering classes desperate for some way of standing apart from their fellow man.
If "bish" and "bishop" convey the exact same meaning in the dynamic of the social context then the "op" is wasted resources. Surely? That's what you've said.
If the beta minus American social dynamic uses "bishop" when an obvious shorter synonym conveys the meaning it must be because, if only on evolutionary principles, there's a felt need to extend the usage of the vocalisation machinery or to get to the bottom of the page more easily in an essay in which bishops (the plural is okay) are mentioned.
*Isn't Gracie witty eh what?